1. Field of the Invention
The present invention relates to a figure encoder for encoding figures primarily comprised of lines, such as drawings or maps, so as to facilitate registration of such figures to computers and, more particularly, to such a figure encoder especially suitable for closed figures.
2. Description of the Prior Art
Recently, much effort has been made to develop computerized administration systems for figures primarily comprised of lines, such as logical circuit diagrams, architectural drafts, or maps, by encoding such figures to store them in a data-base, and utilizing the recorded information for CAD, CAM, or other computerized operations.
One conventional method for executing the registration of the figures is to record the figures in an image memory by means of an imaging device and to extract figure data automatically by methods of pattern recognition. In this method, a sufficiently high standard of accuracy in the pattern recognition has not yet been achieved, so that corrections of recognition errors which requires enormously cumbersome procedures are indispensable. Moreover, the types of images that can be handled by this method are still extremely limited.
Registration of those images whose complexity prohibit application of the method just described have conventionally been accomplished by manual operations of specifying each point on the figures, representing the figures by the sets of coordinates of the specified points, and registering these sets of coordinates as figure data to computers by means of a digitizer. A variation of this method in which images are scanned by a scanner, stored in an image memory and displayed on a display on which coordinate points are specified by means of a pointing device is also conceivable. Both of these methods require a large number of points to be specified manually, which poses serious problems concerning the time required and the accuracy of the procedure.